Speaker
Описание
We discuss a framework for studying the properties of the Lefschetz
thimbles decomposition for lattice fermion models. Non-iterative
solver for the inversion of fermion determinants forms the core of the
method. It allows us to solve the gradient flow (GF) equations taking
into account the fermion determinant exactly. Being able to do so, we
can find both real and complex saddle points of the lattice action and
describe the structure of the Lefschetz thimbles decomposition for
large enough lattices to extrapolate our results to the thermodynamic
limit.
We show two possible applications of this technique. First of all, the
knowledge about the saddle points can help us to simplify the
structure of the Lefschetz thimbles decomposition and to alleviate the
sign problem. The second application is systematic building of the
quasi-classical approximation taking into account Gaussian
fluctuations around exact saddle points.
